首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   201059篇
  免费   3092篇
  国内免费   83篇
耳鼻咽喉   1331篇
儿科学   7264篇
妇产科学   3599篇
基础医学   20277篇
口腔科学   1882篇
临床医学   15015篇
内科学   35879篇
皮肤病学   959篇
神经病学   18790篇
特种医学   9469篇
外国民族医学   3篇
外科学   32317篇
综合类   2841篇
一般理论   42篇
预防医学   20414篇
眼科学   3595篇
药学   11624篇
中国医学   660篇
肿瘤学   18273篇
  2023年   189篇
  2022年   267篇
  2021年   611篇
  2020年   386篇
  2019年   628篇
  2018年   22429篇
  2017年   17760篇
  2016年   19994篇
  2015年   1551篇
  2014年   1718篇
  2013年   2122篇
  2012年   8821篇
  2011年   22905篇
  2010年   19845篇
  2009年   12459篇
  2008年   21055篇
  2007年   23364篇
  2006年   2354篇
  2005年   3966篇
  2004年   5140篇
  2003年   5847篇
  2002年   3898篇
  2001年   479篇
  2000年   577篇
  1999年   401篇
  1998年   529篇
  1997年   483篇
  1996年   352篇
  1995年   348篇
  1994年   294篇
  1993年   266篇
  1992年   186篇
  1991年   208篇
  1990年   228篇
  1989年   172篇
  1988年   156篇
  1987年   130篇
  1986年   104篇
  1985年   119篇
  1984年   119篇
  1983年   122篇
  1982年   156篇
  1981年   124篇
  1980年   134篇
  1978年   68篇
  1977年   68篇
  1976年   66篇
  1974年   74篇
  1938年   61篇
  1932年   59篇
排序方式: 共有10000条查询结果,搜索用时 5 毫秒
21.
22.
Contraceptive use is an important strategy for the prevention of unwanted pregnancy and avoidance of induced abortion. Of all the contraception methods, emergency contraceptive (EC) offers the last chance to achieve this. However, few studies have documented the use of EC among young people in Ghana. This study explored knowledge and usage of EC as well as the factors associated with it among University of Cape Coast students. Data were obtained on the knowledge and usage of ECs among University of Cape Coast students in 2013. Logistic regression analysis was used to investigate the association between students’ socio-demographic characteristics and EC knowledge and use. More male students (72 %) than females (59 %) were sexually active. Fifty-seven percent of the respondents had ever heard of EC and 36 % had ever used EC. Although males were more likely to be sexually active, females were more likely to have knowledge of EC use compared to males. The study underscores the need to increase awareness regarding EC among University students in order to offer them the opportunity that EC provides if other forms of contraceptives are missed.  相似文献   
23.
24.
Gastroesophageal reflux is the most common benign disorder of the esophagus and laparoscopic Nissen fundoplication has become the standard surgical treatment for its treatment. In our area, where the use of bougie calibration is debatable, postoperative dysphagia is encountered often after this surgery although it is usually not permanent. The aim of this study was to investigate the effect of using a soft silicone tube 39 F in diameter for esophageal calibration during laparoscopic Nissen fundoplication on the incidence of postoperative dysphagia. We divided cases scheduled to undergo laparoscopic Nissen fundoplication between January 2009 and November 2010 into two groups, each consisting 25 patients. Esophageal calibration with a 39 F silicone orogastric tube was used for the first group while there was no operative calibration in the second group. The surgical duration was recorded; the presence and severity of the postoperative dysphagia was calculated by using a dysphagia severity scoring system during the 1-year postoperative follow-up. The dysphagia severity scores were significantly lower in group 1 than group 2 on the postoperative second day and at the end of the first week and first month. We did not find a significant difference at the end of the 6-month and first year. There was also no significant difference regarding surgery duration. The use of a soft orogastric tube 39 F in diameter for esophagus calibration during laparoscopic Nissen fundoplication has significantly decreased the incidence of postoperative transient dysphagia without affecting the duration of surgery. Although dysphagia gradually resolves in the majority of patients, a safe and easy calibration method for its prevention is worth developing, and we believe that the use of our method in larger series could be beneficial.  相似文献   
25.
26.
27.
Tranexamic acid (TXA) is an antifibrinolytic drug that reduces surgical blood loss and death due to bleeding after trauma and post‐partum haemorrhage. One key issue for treatment success is early administration. While usually given intravenously, oral and intramuscular use would be useful in specific circumstances. Therefore, an understanding of TXA pharmacokinetics when given via different routes is valuable. The aim of this study was to perform an individual participant data meta‐analysis of pharmacokinetic studies with TXA given to healthy volunteers via different routes. We searched the following databases: PubMed, Web of Science, Wiley Online Library, Elsevier Science Direct and J‐STAGE. Individual subject data were extracted when available, otherwise arithmetic means were used. A population pharmacokinetic model was developed using nonlinear mixed effect modelling. Seven studies were included in the analysis with data from 10 patients for the IV route, six patients for the IM route and 114 patients for the oral route. The pharmacokinetics was ascribed to a two‐compartment model, and the main covariate was allometrically scaled bodyweight. Oral and IM bioavailabilities were 46 and 105%, respectively. For a 70 kg bodyweight, the population estimates were 7.6 L/h for clearance, 17.9 L for the volume of the central compartment, 2.5 L/h for the diffusional clearance and 16.6 L for the peripheral volume of distribution. Larger well‐designed studies are needed to describe the pharmacokinetics of TXA when given IM or as an oral solution before these can be recommended as alternatives to IV.  相似文献   
28.
29.
30.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号